Fuel pumps are used in engine's to pressurize fuel in a fuel delivery system. Some fuel delivery systems are designed for high pressure fuel delivery for direct injection systems. Magnetic solenoid valves (MSV) are utilized in fuel pumps to regulate the fuel flow into a pump chamber during fuel pump operation. Specifically, solenoid valves in fuel pumps may be operated to selectively permit and inhibit fuel flow into a pump chamber from a fuel pump inlet. As a result, the pump chamber may receive fuel from the inlet during an intake stroke and deliver pressurized fuel to downstream components during a delivery stroke.
US 2011/0097228 discloses a high pressure fuel pump having multiple solenoid valves for adjusting the amount of fuel delivered to a fuel rail from the high pressure fuel pump However, the solenoid valve disclosed in US 2011/0097228 may generated ticks, vibrations, etc., during pump operation when the solenoid valve is activated. Therefore, noise, vibration, and harshness (NVH) may be increased in the engine via the high pressure fuel pump disclosed 2011/0097228 and other fuel pumps utilizing solenoid valves. The NVH may not only harm the fuel pump but may also degrade surrounding components. As a result, customer satisfaction may be decreased, component longevity may also be deceased, and the likelihood of component failure may be increased when NVH is generated by the solenoid valve.
The inventors herein have recognized the above issues and developed a method of pressuring fuel for a direct injection fuel system via a fuel pump in an engine. The method includes, during a first mode, adjusting a magnetic solenoid valve (MSV) to control pump outlet pressure and during a second mode, deactivating the MSV and controlling pump outlet pressure via a noise-reducing valve assembly on an inlet side of the fuel pump.
In this way, the solenoid valve in the fuel pump may be disabled for a selected period of time, such as idle or other selected operating conditions while the noise-reducing valve functions to control the pump outlet pressure. Thus, the window of operation of the solenoid valve is decreased, thereby decreasing NVH in the pump generated by the solenoid valve. As a result, component longevity and customer satisfaction are increased. Further it will be appreciated that in some examples the noise-reducing may be passively actuated. Therefore, the noise-reducing valve may generate a small amount of (e.g., substantially zero) NVH when compared to the solenoid valve. Consequently, the technical results achieved via the fuel pump include reducing the NVH generated in the pump during certain operating conditions, such as during idle and/or other low speed conditions, while still providing sufficient pressure control and fuel supply to the fuel pump so that sufficient fuel can be delivered to the engine.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.